This application is directed to an apparatus for automatic processing of radiation sensitive film. More particularly, the invention is directed to an apparatus for the developing of dental x-ray film.
A variety of self contained apparatus for developing a dental x-ray film are known. These apparatus generally fall into two categories. In the first category are apparatus wherein films are held fixed in a container. The different processing fluids, i.e., the developer, fixer and rinse, are each held in a storage container and are pumped in a sequence one at a time into the container wherein the film is located and then drained from that container. The second category of apparatus utilize separate compartments for the different developing fluids, with the film passing from one compartment to the next.
In the first category of apparatus described above, problems have resulted because of contamination of one of the developing fluids by a further of the fluids because of inherent problems in incomplete removal of each fluid from the tank wherein the film is located. Further, mechanical pumps and the like, besides being expensive, are generally susceptible to wear and tear and as such must be maintained on a very regimented basis in order to keep these systems working.
The second category of apparatus overcome the disadvantages of the first in that the developing fluids are maintained in their own separate containers at all times, and pumps and the like are not needed. In this category of apparatus, one type of structure or another has to be utilized to move the film in sequence through the appropriate developing fluids. In one solution to this problem, a track defined by a plurality of rollers is utilized to pass the films through the sequences of developing fluids. While this type of device certainly has its utility, because the individual dental x-ray films are of small size, and are not on a continuous roll such as camera film would be, at times the individual films can get jammed within the pathway of the apparatus. Since the time the film spends in the individual fluid is critical, especially for the developer, the jamming of the film in the pathway can lead to overdeveloping or the like and thus the loss of the images on the film.
A second type of apparatus which can be generally classified as a transport system utilizes an endless chain belt or the like, or a sliding carriage to move the individual films from one tank of developing fluid to the next. For the most part these systems require the attachment of individual films to individual clips, and the films are essentially developed one at a time. Because of this, in order to process a number of films, the devices essentially require constant operator attention for loading and unloading of the individual films in order to pass them through the device one at a time. Also, since the endless belt, carriage rod or the like must be linear, four tanks are generally used, first a developer tank, then a first rinse, then a fix tank, then a second rinse. The linearity of the endless belt or carriage precludes the use of a single rinse tank for both rinsing operations.